JP3577201B2 - Charged particle beam irradiation device, charged particle beam rotation irradiation device, and charged particle beam irradiation method - Google Patents

Abstract

Provided is a charged-particle beam irradiation apparatus capable of realizing spot-scanning in which the spot of a beam parallel to the axis of incidence thereof is shifted in two axial directions within a radiation area, and having a compact and lightweight design. A pair of scanning electromagnets 33 and 35 that are linked by linkage frames 45 and 47 and generate a scanning field composed of a pair of magnetic fields effective in bending a charged-particle beam 31 by the same angle in mutually opposite directions are rotated by a rotary driving gear 53 having the scanning electromagnets mounted thereon and motors 49a and 49b. Thus, spot scanning in which the spot of a beam parallel to the axis of incidence thereof is shifted in two axial directions can be realized. <IMAGE>

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a charged particle beam irradiation device, a charged particle beam rotation irradiation device, and a charged particle beam irradiation method used in a charged particle beam therapy device or the like.
[0002]
[Prior art]
FIG. 16 is a conventional charged particle beam therapy apparatus disclosed in a report by Pedroni of Switzerland etc. published in, for example, Medical Physics, Vol. 22, pp. 37-53. It is an example of a line rotation irradiation device.
[0003]
In the figure, 100 is a charged particle beam rotary irradiation device, 1 is a particle accelerator, 3 is a transporting electromagnet, 5 is an energy degrader, 7 is a proton beam, 9 is a beam stopper, 10 is a rotating gantry, 11, 13 and 19 is a bending electromagnet, 15 is a focusing electromagnet, 17 is a scanning electromagnet, 21 is an energy degrader, 23 is a dose / position monitor, 25 is a patient, 27 is an irradiation bed, and 29 is a gantry rotation axis.
[0004]
The proton beam generated from the accelerator 1 is carried by the transporting electromagnet 3, passes through the energy degrader 5 as the first stage energy changing means, and becomes a proton beam 7 having a predetermined energy. The proton beam 7 is bent upward from the horizontal direction by the first bending electromagnet 11 and then returned to the horizontal direction again by the bending electromagnet 13.
[0005]
Furthermore, after the proton beam 7 is focused by the focusing electromagnet 15, it is swept up and down by the scanning electromagnet 17. The swept proton beam is bent by the last bending electromagnet 19 so as to be directed directly downward, and is irradiated to the patient 25 through the energy degrader 21 for fine adjustment and the dose / position monitor 23.
[0006]
Here, the electromagnets 11, 13, 15, 17, 19, the energy degrader 21 and the monitor 23 are integrated to constitute an irradiation gantry. The irradiation gantry can rotate around a gantry rotation axis 29 and is called a rotating gantry 10.
[0007]
The proton beam irradiated to the patient 25 is scanned in parallel only in the X-axis direction shown in FIG. 16 by the scanning electromagnet 17 and the bending electromagnet 19. Scanning in the Y-axis direction necessary for treatment is performed by moving the irradiation bed 27, and scanning in the depth direction (Z-axis direction) of the patient 27 is performed by adjusting the proton beam energy by the energy degrader 21. Be done.
[0008]
For example, the length of the rotating gantry 10 in the longitudinal direction is about 10 m, and the length at which the proton beam is launched in the gantry is about 2 m.
[0009]
[Problems to be solved by the invention]
In the conventional charged particle beam therapy apparatus configured as described above, only parallel beam scanning in one axis direction (X axis direction in the above example) can be realized, and the patient 25 is moved in the Y axis direction by the bed 27 during treatment. I needed to. Such a movement poses a problem that the patient may feel uncomfortable or fearful, and at the same time cause a positional shift of the irradiation area.
[0010]
In the conventional apparatus as described above, the scanning electromagnet 17 needs to be installed upstream of the deflection electromagnet 19 in order to scan the beam in parallel, and the proton beam scanned vertically by the scanning electromagnet 17, that is, the charged beam is charged. The deflection electromagnet 19 that deflects the particle beam has been large. As a result, the total weight of the above-described rotating gantry 10 for treatment has become 100 tons or more. In addition, since the bending electromagnet 19 is a large one having a magnetic pole width of several tens of centimeters, there is a problem that the production cost becomes extremely high when superconducting.
[0011]
The present invention has been made in order to solve the above-described problems, and has realized parallel beam scanning in two axial directions in an irradiation area without moving a bed, and has also reduced the size and weight of a rotating gantry. It is an object to provide a charged particle beam irradiation device, a charged particle beam rotation irradiation device, and a charged particle beam irradiation method.
[0012]
[Means for Solving the Problems]
In view of the above-mentioned object, the present invention generates a scanning field consisting of a set of fields in which a charged particle beam is bent by the same angle in opposite directions to each other, so that the distance from the incident axis of the charged particle beam to the scanning field is generated. As a scanning field generating unit that changes the irradiation position of the charged particle beam on the irradiation object, a rotating unit that rotates the scanning field generating unit with the incident axis to the scanning field as a rotation center axis, A charged particle beam energy adjusting means provided between the scanning field generator and the irradiated object, and changing the irradiation depth of the charged particle beam from the surface of the irradiated object by adjusting the energy of the charged particle beam, Around the rotation center axisSet discretelyRotation angle information, radial position information of the rotation, and irradiation depth information of the irradiation target, has a predetermined irradiation position information, among the rotation angles included in the irradiation position informationPredeterminedAfter rotating the rotating part corresponding to the rotation angle of the, based on the radial position corresponding to the rotation angle included in the irradiation position information, and the irradiation depth,Scanning field generatorThe intensity of the scanning field, and controlling the charged particle beam energy by the charged particle beam energy adjusting means, by irradiating the charged particle beam, the radial position included in the irradiation position information corresponding to the rotation angle and After performing the irradiation of the charged particle beam at the irradiation depth, control means for performing irradiation control to perform the series of charged particle beam irradiation for the other rotation angles included in the irradiation position information, It is in the charged particle beam irradiation device.
[0013]
The present invention also provides a scanning field including a set of fields that bend the charged particle beam by the same angle in opposite directions to each other, so that the distance from the incident axis of the charged particle beam to the scanning field is set as the distance to the irradiated object. A scanning field generating unit that changes the irradiation position of the charged particle beam in, a rotating unit that rotates the scanning field generating unit with the incident axis to the scanning field as a rotation axis, and the scanning field generating unit. A charged particle beam energy adjusting means provided between the irradiation object and changing the irradiation depth of the charged particle beam from the surface of the irradiation object by adjusting the energy of the charged particle beam; and aroundSet discretelyRotation angle information, irradiation depth information of the irradiation object, and the rotation angle, corresponding to the irradiation depth, for changing the sweep speed of the charged particle beam in inverse proportion to the distance from the rotation center axis, Consisting of scanning pattern information, which is a time-dependent function that defines the intensity of the scanning field, has preset irradiation position information, and the rotation angle included in the irradiation position information is determined by the rotation of the rotating unit and the irradiation depth. Controls the irradiation position by controlling the charged particle beam energy by the charged particle beam energy adjusting means, and performs the charged particle beam irradiation in the radial direction of rotation based on the scanning pattern corresponding to the rotation angle and the irradiation depth. And a control unit for performing irradiation control.
Further, in the above apparatus, the control unit performs irradiation at a predetermined rotation angle among the rotation angles included in the irradiation position information, an irradiation depth set at the rotation angle, and a scanning pattern, and then performs the irradiation at the irradiation position. The above-described series of charged particle beam irradiation is performed for another rotation angle included in the information.
[0014]
The invention also providesThe scanning field generating unit is characterized in that the scanning field generating unit is disposed on one side of the charged particle beam incident axis.
[0015]
The invention also providesA charged particle beam deflecting means for deflecting the charged particle beam so as to be perpendicular to the irradiation surface of the irradiation object; and any one of the above-mentioned charging devices installed downstream of the deflecting means with respect to the traveling direction of the charged particle beam. The charged particle beam rotary irradiation device includes a particle beam irradiation device, and a rotation moving unit that integrally rotates the deflection unit and the charged particle beam irradiation unit.
[0016]
Also, the present invention provides a scanning field generating means for generating a scanning field consisting of a set of fields which bend the charged particle beam by the same angle in opposite directions to each other, and converts the incident charged particle beam to the scanning field of the charged particle beam. A method of irradiating a charged particle beam that scans on a straight line on a plane perpendicular to the incident axis, and irradiates the irradiated area of the irradiation target with a charged particle beam by rotating the scanning field generating means around the incident axis. And around the rotation center axis.Set discretelyRotation angle information, radial position information of the rotation, and irradiation depth information of the irradiation object, has predetermined irradiation position information, based on the irradiation position information, the rotation angle of the scanning field generating means Setting the radial position and the irradiation depth corresponding to the rotation angle set in the first step, which are included in the irradiation position information, and setting the set radial position and the irradiation depth. Correspondingly, a second step of setting the field intensity of the scanning field generating means and the energy of the charged particle beam, and irradiating the irradiated object by controlling the charged particle beam according to the settings in the first step and the second step. A third step to be performed, and an unirradiated radial position and an unirradiated radial position and an irradiation depth included in the irradiation position information and corresponding to the rotation angle set in the first step. A fourth step of repeating the second step to the third step until there is no projection depth, and there is no unirradiated rotation angle included in the irradiation position information with respect to another rotation angle included in the irradiation position information. And a fifth step of repeating the first to fourth steps up to the fifth step.
[0017]
Also, the present invention provides a scanning field generating means for generating a scanning field consisting of a set of fields which bend the charged particle beam by the same angle in opposite directions to each other, and converts the incident charged particle beam to the scanning field of the charged particle beam. A method of irradiating a charged particle beam that scans on a straight line on a plane perpendicular to the incident axis, and irradiates the irradiated area of the irradiation target with a charged particle beam by rotating the scanning field generating means around the incident axis. And around the rotation center axis.Set discretelyRotation angle information, irradiation depth information of the irradiation object, and the rotation angle, corresponding to the irradiation depth, for changing the sweep speed of the charged particle beam in inverse proportion to the distance from the rotation center axis, It has preset irradiation position information consisting of scanning pattern information that is a time-dependent function that defines the intensity of the scanning field, and is included in the irradiation position information.A first step of setting the charged particle beam energy based on the irradiation depth, the rotation angle of the scanning field generating means based on the rotation angle corresponding to the irradiation depth, and the scanning pattern corresponding to the rotation angle and the irradiation depth, respectively; A second step of scanning the charged particle beam based on the irradiation depth, the rotation angle and the scanning pattern, and irradiating the irradiation target with an irradiation object, and a first step until there is no unirradiated rotation angle included in the irradiation position information. And a third step of repeating the second step;In the charged particle beam irradiation method.
Further, in the above method, at a predetermined rotation angle among the rotation angles included in the irradiation position information, an irradiation depth set at the rotation angle, and after performing irradiation with a scanning pattern, the irradiation angle is included in the irradiation position information. The above-described series of charged particle beam irradiation is performed for other rotation angles.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a charged particle beam irradiation apparatus according to one embodiment of the present invention. Reference numeral 20 denotes a charged particle beam irradiation apparatus, 30 denotes a beam incident axis, 31 denotes a charged particle beam (for example, a proton beam, a carbon beam, or the like), and 33 and 35 denote directions opposite to each other. A uniform magnetic field having the same length (length along the incident axis 30) is generated, and two scanning electromagnets are installed at regular intervals along the incident axis 30 of the charged particle beam. is there. 41 indicates the magnetic pole width of the scanning electromagnets 33 and 35, and 43 indicates the magnetic pole gap. Reference numerals 45 and 47 denote connection frames connecting the electromagnets 33 and 35.
[0027]
Reference numeral 53 denotes a rotation driving gear for rotating the charged particle beam irradiation device 20 about the rotation shaft 37, and 49a and 49b denote motors for rotating the gear 53. 57 is an irradiation object, 56 is an irradiation area, and 55 is an example of the trajectory of the swept charged particle beam. FIG. 2 is a sectional view taken along the line AA of FIG. 1, and 34 indicates the direction of the magnetic field of the scanning electromagnets 33 and 35. FIG. 3 is a transparent side view of the scanning electromagnets 33 and 35 viewed from the direction of arrow B in FIG. 1 and shows a scanning state of the charged particle beam.
[0028]
The operation will be described below. The incident charged particle beam 31 is first bent by the scanning electromagnet 33 by a certain angle and then again by the scanning electromagnet 35 having the same magnetic field direction and the same strength and effective magnetic field length in the opposite direction by the scanning electromagnet 33. Then, it is irradiated as a beam parallel to the original charged particle beam 31. As a result, the charged particle beam scanned along the scanning trajectory indicated by the sweep trajectory 55 is always parallel to the incident beam 31.
[0029]
Further, the electromagnets 33 and 35 are integrated by the connecting frames 45 and 47, and are rotated around the rotation shaft 37 by rotating means such as motors 49a and 49b. A two-dimensional irradiation area is realized.
[0030]
When the intensity and the cross-sectional shape of the beam 31 are constant, the central portion of the irradiation area 56 through which the rotating shaft 37 passes receives more particles per unit area than the outside. By controlling the currents of the scanning electromagnets 33 and 35 so that the sweep speed is inversely proportional to the distance that the beam 31 is scanned from the incident axis 30 along the sweep trajectory 55, and by sufficiently making the rotation steps of scanning by rotation sufficiently fine, In the irradiation area 56, the uniform irradiation particle number density distribution shown in FIG. 4 can be realized.
[0031]
In addition, since the magnetic fields generated by the scanning electromagnets 33 and 35 are uniform, the relationship between the magnitude of the flowing current and the distance at which the beam 31 is scanned from the incident axis 30 is directly proportional as shown in FIG. . Therefore, by controlling the current I (t) of the scanning electromagnets 33 and 35 as shown in FIGS. 6 and 7, the sweep speed can be made inversely proportional to the distance that the beam 31 is scanned from the incident axis 30.
[0032]
In the above embodiment, the scanning electromagnets 33 and 35 have the same magnetic field strength and the same effective magnetic field length. However, if the beam 31 is bent in the opposite direction by the same angle, the magnetic field strength and the effective magnetic field are not changed. The lengths need not be the same.
[0033]
In the above embodiment, the two electromagnets 33 and 35 are used to scan the charged particle beam 31 in parallel to the incident axis 30. If a pair of scanning magnetic fields that can be bent by the same angle can be generated, one or more electromagnets or permanent magnets designed to generate the scanning magnetic field (for example, the spatial arrangement of the permanent magnets can be mechanically varied) A scanning magnetic field generator including a permanent magnet configured as described above may be used.
[0034]
For example, FIG. 8 shows an example in which two C-shaped scanning electromagnets 33 and 35 are used as the scanning magnetic field generating means. As can be seen from FIG. 3, the magnetic pole width 41 of the electromagnet 33 may be smaller than the magnetic pole width 41 of the electromagnet 35, so that the weight of the entire irradiation device 20 can be reduced. In an extreme case, the cross section of the magnetic pole of the electromagnet 33 may be fan-shaped. Further, since the scanning of the magnetic pole gaps 43 of the scanning electromagnets 33 and 35 in the direction of the magnetic pole gaps 43 does not need to be performed, the magnetic pole gaps 43 can be reduced to about the cross-sectional size of the charged particle beam 31 to be incident.
[0035]
In this embodiment, a compact charged particle beam irradiation apparatus with a simple structure that performs parallel beam scanning in the two axial directions can be realized.
[0036]
Embodiment 2 FIG.
FIG. 9 is a diagram showing a configuration of a charged particle beam rotary irradiation device used as a charged particle beam therapy device or the like according to another embodiment of the present invention. The same or corresponding parts as those of the conventional and the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted. In the charged particle beam rotation irradiation device 101 of FIG. 9, the charged particle beam irradiation device 20 of the above-described embodiment is provided between the bending electromagnet 19 and the energy degrader 21. Therefore, since the beam 31 before scanning is incident on the bending electromagnet 19, it is very small as compared with the conventional one. Thus, the position of the patient 25 as the irradiation target can be set on the gantry rotation axis 29 of the rotating gantry 10.
[0037]
Next, the operation will be described. In the charged particle beam rotating irradiation apparatus 101, the high energy charged particle beam emitted from the accelerator 1 is carried to the first stage energy degrader 5 by the transporting electromagnet 3. The charged particle beam 31 having a predetermined energy that has passed through the energy degrader 5 is bent upward from the horizontal direction by the first bending electromagnet 11, and is returned to the horizontal direction again by the bending electromagnet 13.
[0038]
Further, the charged particle beam is focused by the focusing electromagnet 15 and then incident on the deflection electromagnet 19. As described above, in the apparatus 101 of this embodiment, the beam is not scanned in front of the bending electromagnet 19, and the beam 31 is bent by the electromagnet 19 as a thin pencil beam so as to be directed directly downward. Therefore, both the magnetic pole width 22 and the magnetic pole gap 18 of the bending electromagnet 19 shown in FIG. 10 can be reduced, and the total capacity and the total weight of the rotating gantry 10 can be reduced.
[0039]
In the conventional apparatus, the magnetic pole width 22 of the bending electromagnet 19 has to cover the charged particle beam scanned by the scanning electromagnet 17 shown in FIG.
[0040]
Further, in this embodiment, since the bending electromagnet 19 is small, it can be easily made superconductive together with the other bending electromagnets 11 and 13, and the rotating gantry 10 can be further reduced in size and weight. Further, the charged particle beam 31 emitted from the bending electromagnet 19 is scanned by the scanning electromagnets 33 and 35 so as to be always parallel to the incident direction as described in the first embodiment.
[0041]
In this embodiment, as shown in FIG. 9, beam scanning can be realized in parallel in two axial directions, so that the movement of the irradiation bed 27 on which the patient 25 is placed becomes unnecessary, and the irradiation position accuracy of the treatment apparatus is reduced. There is an effect that improvement can be achieved.
[0042]
When the charged particle beam is a proton beam having an energy of about 250 MeV required for the treatment of a deep tumor (residency against a magnetic field is 2.43 Tesla meters) and the irradiation area of 20 cm in diameter is scanned, the bending electromagnet 19 is made superconductive. In this case, the size can be reduced to about 40 cm, and the length from end to end of the charged particle beam irradiation apparatus 20 including the scanning electromagnets 33 and 35 can be reduced to about 120 cm. Can be suppressed.
[0043]
As a result, unlike the conventional apparatus, the patient 25 can be placed on the gantry rotation axis 29 of the rotating gantry 10 while realizing two-dimensional parallel beam scanning, and the structure of the rotating gantry 10 can be greatly simplified. Further, it is possible to reduce the weight of a treatment apparatus having a rotating gantry that generates the above-mentioned 250 MeV proton beam to less than half of the conventional treatment apparatus.
[0044]
Although FIG. 9 shows that the energy degrader 21 and the dose / position monitor 23 are mounted on the rotating gantry 10, the energy degrader 21 and the dose / position monitor 23 are separate from the rotating gantry 10. May be provided.
[0045]
Embodiment 3 FIG.
FIG. 11 is a diagram showing a configuration of a charged particle beam irradiation apparatus according to another embodiment of the present invention. In the charged particle beam irradiation apparatus of FIG. 1, a magnetic field is generated by an electromagnet or the like as a scanning field. However, in the charged particle beam irradiation apparatus 20 of this embodiment, a gap is provided between two electrodes facing each other. A scanning electric field is generated as a scanning field in between.
[0046]
In FIG. 11, 93a, 93b, 95a and 95b are electrodes, 97 is an insulator supporting the electrodes, 102 is a box made of stainless steel or the like supporting the electrodes and the insulators and the like, 99a and 99b are power supplies, 103 is a cable for supplying a voltage to each of the electrodes 93a, 93b, 95a and 95b, 105 is a cable connector, and 49 is a motor for rotating the box 102 via a rotation driving gear 53 on which the box 102 is mounted. .
[0047]
The electrodes 93a, 93b, 95a and 95b generate electric fields whose directions are opposite to each other, and scan the beam parallel to the incident direction by bending the incident charged particle beam 31 by the same angle in the opposite direction. I do. Further, by rotating the entire box 102, two-dimensional parallel beam scanning can be realized in the irradiation area.
[0048]
Further, the charged particle beam irradiation device according to this embodiment can be used as the charged particle beam irradiation device 20 in the charged particle beam rotation irradiation device 101 of the second embodiment.
[0049]
Embodiment 4 FIG.
FIG. 12 is a diagram showing a configuration of a control portion of the charged particle beam rotary irradiation device according to the present invention. This control section controls the charged particle beam rotary irradiation apparatus shown in FIG. 9, for example, and particularly extracts and shows a section related to beam scanning control.
[0050]
In FIG. 12, reference numeral 200 denotes a control device composed of, for example, a personal computer, etc., 201 denotes an input / output control unit (hereinafter, I / O), 202 denotes a RAM, which is a temporary storage unit, and 203 denotes various information such as beam irradiation setting conditions. A stored database, 204 is a CPU serving as a processing unit, 205 is a ROM for storing a control program and the like, 206 is an interface (hereinafter referred to as I / F) with another device, and 207 interconnects these. It is a bus. The control device 200 includes the beam stopper 9, the energy degrader 21, the dose / position monitor 23, the irradiation bed 27, the motors 49, 49a, 49b of the irradiation device 20, the electromagnets 33, 35, the electrodes 93a, 93b, Scanning field generators corresponding to 95a and 95b are connected.
[0051]
FIG. 13 is a flowchart of the control performed by the control device 200. The control device 200 operates according to a program P stored in the ROM 205, for example.
[0052]
Hereinafter, the control operation will be described with reference to FIGS. First, a three-dimensional position coordinate group [Pi: i = 1, 2,. . . , N], for example, [(θi, ri, Zi), i = 1, 2,. . . , N] (θ is the angular direction, r is the radial direction, and Z is the depth direction) is loaded via the I / F 206 to the control device 200 that controls the irradiation system from a setting table created in advance. (Step S1).
[0053]
Next, the patient 25 is placed on the irradiation bed 27, and the patient 25 is fixed and aligned (step S2). This step S2 may be performed by positioning the movable irradiation bed 27, but may require manual operation. Next, the thickness of the energy degrader 21 is set according to the irradiation position coordinates Zi (initial value i = 1). Then, the rotation angles and the magnetic field strengths of the scanning electromagnets 33 and 35 are set in accordance with the irradiation position coordinates (θi, ri) (step S3).
[0054]
Next, the charged particle beam 31 is irradiated (step S4), and the number and position of the incident particles of the charged particle beam 31 are measured by the dose / position monitor 23 (step S5). Next, the position coordinates measured in step S5 are compared with the position coordinates set in step S3 (step S6). If they do not match, the process proceeds to step S8 in which the beam 31 described below is stopped. If the position coordinates of the measurement and the set position match in the comparison result of step 6, it is determined whether or not the integrated value of the number of particles measured in step S5 is equal to or larger than the set number of particles at a predetermined position determined before starting irradiation. A determination is made (step S7). If not, the process returns to step S5, and if so, the charged particle beam 31 is stopped using the beam stopper 9 (step S8).
[0055]
Next, it is determined whether or not the irradiation is to be terminated (step S9). If the irradiation is to be continued, i is increased by one, and the process returns to step S3. If the irradiation is to be terminated, the process is terminated in step S10.
[0056]
In the above method, steps S3 to S9 are repeatedly executed from i = 1 to i = n, and the position coordinate group [(θi, ri, Zi), i = 1, 2,. . . , N], a predetermined number of particles [Ni, i = 1, 2,. . . , N].
[0057]
Here, the effect is the same even if the execution order of step S1 and step S2 is changed. Further, in the above method, since the rotation speed of the scanning electromagnets 33 and 35 is lower than the scanning speed by the magnetic field intensity and the scanning speed by the energy degrader 21, the scanning angle in the other two directions is maintained while the rotation angle θi is kept constant. Performing earlier can reduce the overall time required for irradiation.
[0058]
In the above description, as the energy changing means, the thickness of the energy degrader 21 is changed, but other energy changing means, such as a synchrotron particle accelerator, may be used. Further, the beam stopper 9 has been described as an example of the charged particle beam stopping means, but other beam stopping means (for example, stopping a particle accelerator or the like) may be used.
[0059]
Further, a three-dimensional position coordinate group [Pi: i = 1, 2,. . . , N], the column-based coordinates are used as an example, but other coordinate systems obtained by deforming the column-based coordinates can be applied. In the above description, the irradiation device 20 including the scanning electromagnets 33 and 35 is used as the scanning means for the charged particle beam. However, the present invention is not limited to this. Scanning means for other charged particle beams, for example, Embodiment 3 Irradiation device 20 or the like provided with the above scanning electrode may be used.
[0060]
Embodiment 5 FIG.
FIG. 14 shows a flowchart of another method of control performed by the control device 200 of FIG. As in the fourth embodiment, it is assumed that the initial energy of the charged particle beam 31 is already constant by the setting of the energy degrader 5.
[0061]
Hereinafter, the control operation will be described with reference to FIGS. First, a position coordinate group [(Zi, θij), i = 1, 2,. . . , M, j = 1, 2,. . . , N] and the time characteristics [Iij (t), j = 1, 2,. . . , N] are loaded via the I / F 206 from the setting table created in advance into the control device 200 controlling the irradiation system (step S1). These position coordinates are obtained by using a position coordinate Zi describing the depth, a rotation angle θij at the depth, and a time characteristic Iij (t) of the scanning pattern in the diameter or the radial direction at the angle. Represents.
[0062]
Next, the patient 25 is placed on the irradiation bed 27, and the patient 25 is fixed and aligned. This step S2 may be performed by positioning the movable irradiation bed 27, but may require manual operation. Next, the thickness of the energy degrader 21 is set according to the irradiation position coordinates Zi (initial value i = 1) (step S3). Next, the rotation angles of the scanning electromagnets 33 and 35 are set to θij (initial value j = 1), and the scanning pattern of the current flowing through the electromagnets is set to Iij (t).
[0063]
Next, the charged particle beam 31 is irradiated (step S5), and the current is scanned a predetermined number of times according to the current scanning pattern of the scanning electromagnets 33 and 35 set in step S4. That is, a current is supplied to the scanning electromagnets 33 and 35 in accordance with Iij (t) indicating a preset current scanning pattern, for example, between the radius or the diameter of the cylindrical coordinate system (step S6). When the intensity of the incident charged particle beam fluctuates with time, the current scanning pattern is determined based on the time increase rate of the number of charged particles measured in real time by the dose / position monitor 23 in step S10 described below. Control to form the desired irradiation particle number distribution.
[0064]
When the scanning of the predetermined number of times is completed, the beam 31 is stopped using the beam stopper 9 (step S7). Next, it is determined whether or not the irradiation is to be ended (step S8). If the irradiation is to be continued in the determination in step S8, it is determined whether or not to move to the next position coordinate Zi corresponding to the next depth (step S9). If to move to the next position coordinate Zi, i is increased by one, j is set to 1 as an initial value, and the process returns to step S3. If it does not move to the next position coordinate Zi, j is incremented by one and the process returns to step S4.
[0065]
In this manner, steps S3 to S9 and steps S3 to S8 are repeated from i = 1 to i = m and j = 1 to j = n to irradiate a predetermined irradiation area. .
[0066]
During the irradiation, the number and position of the irradiated charged particles are constantly measured by the dose / position monitor 23 (step S10), and the position coordinates measured in step S10 and the position coordinates θij set in step S4 are compared. If they match, the process returns to step S10. If they do not match, the charged particle beam 31 is stopped using the beam stopper 9 (step S8).
[0067]
Here, the scanning pattern Iij (t) will be described. FIG. 15 shows an example of a scanning trajectory of the charged particle beam 31 in the charged particle beam irradiation method of this embodiment. Numeral 38 indicates a cross section of the charged particle beam 31 scanned. Although FIG. 15 shows scanning only in a section with a radius, scanning may be performed over a section with a diameter.
[0068]
Further, in the charged particle beam irradiation method described in this embodiment, when the number of particles and the beam shape of the incident charged particle beam 31 per unit time are constant, the scanning pattern Iij (t) is changed as shown in FIG. If (radius) or FIG. 7 (diameter) is used, a flat particle number density distribution as shown in FIG. 4 can be realized when the irradiation area is scanned as shown in FIG.
[0069]
By making the scanning pattern Iij (t) basically proportional to the square root of the time variable t as shown in FIG. 6 and FIG. 7, the scanning speed is changed to the distance from the rotation center axis in the scanning shown in FIG. It can be controlled in inverse proportion. This is because the current flowing through the electromagnets 33 and 35 is proportional to the scanning distance as shown in FIG. Further, the inverse proportional relationship between the sweep speed and the distance from the rotation center axis can realize the flat particle number density distribution shown in FIG.
[0070]
Further, the magnetic poles of the scanning electromagnets 33 and 35 shown in FIG. 1 are better when scanning over only the radius at each rotation angle about the incident axis 30 shown in FIG. 15 than when scanning over diameter. The width 41 and the length along the beam direction can each be shortened, and the size and weight of the irradiation device can be reduced.
[0071]
In the above description, the irradiation device 20 including the scanning electromagnets 33 and 35 is used as the scanning means for the charged particle beam. However, the present invention is not limited to this. Scanning means for other charged particle beams, for example, Embodiment 3 Irradiation device 20 or the like provided with the above scanning electrode may be used. In this case, the voltage supplied to the irradiation device 20 is changed according to the scanning pattern Iij (t). That is, a voltage scanning pattern Iij (t) is obtained.
[0072]
Further, the devices and methods of the above embodiments are not limited to devices for charged particle beam therapy, and can be widely applied to fields requiring irradiation or injection of charged particle beams, such as the semiconductor field and the material field.
[0073]
【The invention's effect】
As described above, according to the present invention, the scanning field generating means for generating a scanning field consisting of a set of fields which bend the charged particle beam in the opposite direction by the same angle, and the scanning field with the incident axis of the charged particle beam as the center. Since the charged particle beam irradiation apparatus is constituted by the rotating means for rotating the generating means, it is possible to provide a small charged particle beam irradiation apparatus capable of performing biaxial parallel beam scanning.
[0074]
Further, since the scanning field generating means generates a magnetic field, it is possible to provide a small charged particle beam irradiation apparatus which generates a scanning magnetic field.
[0075]
Further, since the scanning field generating means generates an electric field, it is possible to provide a small charged particle beam irradiation device which generates a scanning electric field.
[0076]
Further, in the present invention, the charged particle beam deflecting means for deflecting the charged particle beam so as to be perpendicular to the irradiation surface, and installed at the downstream side of the deflecting means, and the charged particle beams are opposite to each other by the same angle in the opposite directions. A scanning field generating unit configured to generate a scanning field including a set of bending fields; and a rotating unit configured to rotate the scanning field generating unit around an incident axis of the charged particle beam. A charged particle beam irradiation device to be scanned, a charged particle beam energy adjustment device provided between the charged particle beam irradiation device and the irradiation target, and a rotation for integrally rotating at least the deflection device and the charged particle beam irradiation device Since the charged particle beam rotating irradiation device is constituted by the moving means, a small charged particle beam irradiation device capable of performing biaxial parallel beam scanning is provided. There is no need to move the irradiated body, and since the charged particle beam irradiation device can miniaturize the deflecting means so provided downstream of the deflecting means, it is possible to provide a compact charged particle beam rotary irradiation system.
[0077]
Further, in the present invention, in the charged particle beam rotating irradiation device, the charged particle beam is incident on the deflecting unit from a rotation axis direction of the rotation moving unit, and the deflecting unit is configured to charge the incident light from a direction parallel to the irradiation surface. Since three deflection electromagnets for deflecting the particle beam so as to be perpendicular to the irradiation surface by three 90-degree deflections are included, and the irradiation target is arranged on the rotation axis of the rotation moving means, It is possible to provide a charged particle beam rotating irradiation device in which the rotation moving means can be easily controlled.
[0078]
Further, according to the present invention, in the charged particle beam rotating irradiation apparatus, since each of the deflection electromagnets of the deflecting means is constituted by a superconducting electromagnet, a further small charged particle beam rotating irradiation apparatus can be provided.
[0079]
Further, in the present invention, a scanning field generating section for generating a scanning field consisting of a set of fields for bending the charged particle beam in opposite directions by the same angle, and the scanning field generating section around the incident axis of the charged particle beam. A charged particle beam irradiation device that includes a rotating unit for rotating and scans the charged particle beam; and a charged particle beam energy adjustment device that adjusts energy of the charged particle beam provided between the charged particle beam irradiation device and the irradiation target. Means, a dose / position measuring means provided between the charged particle beam irradiation device and the irradiation target and monitoring the dose and position of the irradiated charged particle beam, a means for stopping the charged particle beam, Control means connected to the control means for performing scanning control, wherein the control means controls a coordinate group [Pi: i = 1, 2,. . . , N] (i = 1 as an initial value), the first means for setting the rotation angle of the scanning field generator, the field intensity, and the energy of the charged particle beam, and the charged particle beam according to the above setting. A second means for irradiating, when the number of particles irradiated with the charged particle beam is equal to or more than a preset number of particles, and when the irradiation position coordinates of the charged particle beam coincide with the preset position coordinates A third means for stopping the charged particle beam in any of the cases where the irradiation is not performed, and judging whether or not the irradiation to all the irradiation regions has been completed when the charged particle beam is stopped. If not, increase the i by one, change the rotation angle of the scanning field generator, the field strength, and the energy of the charged particle beam in a predetermined order, and change the first to third means. Start repeatedly And a fourth means for terminating the irradiation if completed, so that the charged particle beam irradiation apparatus can perform irradiation of an accurate dose to an accurate position without moving an object to be irradiated. A particle beam irradiation device can be provided.
[0080]
In the charged particle beam irradiation apparatus according to the present invention, in the fourth means, the rotation angle of the scanning field generating section is kept constant, and the field intensity and the charged particle beam energy of the scanning field generating section are set to predetermined values. The first means to the third means are repeatedly activated while changing in the order of the above. Therefore, by reducing the number of adjustments of the rotation angle having a slow change speed, the overall time required for irradiation is reduced. A particle beam irradiation device can be provided.
[0081]
Further, in the present invention, a scanning field generating section for generating a scanning field consisting of a set of fields for bending the charged particle beam in opposite directions by the same angle, and the scanning field generating section around the incident axis of the charged particle beam. A charged particle beam irradiation device that includes a rotating unit for rotating and scans the charged particle beam; and a charged particle beam energy adjustment device that adjusts energy of the charged particle beam provided between the charged particle beam irradiation device and the irradiation target. Means, a dose / position measuring means provided between the charged particle beam irradiation device and the irradiation target and monitoring the dose and position of the irradiated charged particle beam, a means for stopping the charged particle beam, Control means connected to the control means for performing scanning control. The control means controls a coordinate group [(Zi, θij), i = 1, 2,. . , M, j = 1, 2,. . . , N], the first means for setting the energy of the charged particle beam to be irradiated in accordance with the position coordinate Zi (i = 1 as an initial value) of the irradiation depth, and setting the rotation angle of the scanning field generator to θij ( The second means for setting the time characteristic of the scanning pattern to Iij (t) at j = 1) as an initial value, and irradiating a charged particle beam in accordance with the above setting, and the time characteristic Iij (t) of the scanning pattern is used for the above. A third means for driving the scanning field generating unit to scan the charged particle beam a predetermined number of times; and, in parallel with the scanning of the third means, the irradiation position coordinates of the charged particle beam are set to predetermined position coordinates. A fourth means for determining whether or not they match each other, and when the scanning has been performed a predetermined number of times and when the irradiation position coordinates of the charged particle beam do not match the set position coordinates. Fifth means for stopping the charged particle beam, and judging whether or not the irradiation to all the irradiation areas has been completed when the charged particle beam has been stopped. If not, it is determined whether or not to change the position coordinates Zi of the irradiation depth to the next value. If not, j is increased by one, and the above-described second to fifth means are repeated. In the case where the charged particle is activated and changed, the value of i is increased by one, the value of j is set to 1 as an initial value, and the first means to the fifth means are repeatedly activated to activate the charged particle. The use of the beam irradiation device provides a charged particle beam irradiation device capable of irradiating an accurate dose to an accurate position without moving an irradiation target.
[0082]
According to the present invention, in the charged particle beam irradiation apparatus, the scanning field generating unit sets the time characteristic Iij (t) of the scanning pattern to Iij (t) ∝√t, so that more uniform irradiation can be performed. An irradiation device can be provided.
[0083]
Further, in the present invention, the charged particle beam is bent on a straight line on a plane perpendicular to the incident axis thereof by a scanning field generating means for generating a scanning field consisting of a set of fields which bends the charged particle beam in the opposite directions by the same angle. And irradiating the irradiation area with the charged particle beam by rotating the scanning field generating means around the incident axis, wherein a coordinate group [Pi: i = 1, 2,. . . , N] (i = 1 as an initial value), the first step of setting the rotation angle of the scanning field generating means, the field strength, and the energy of the charged particle beam, and changing the charged particle beam according to the above setting. The second step of irradiating, when the number of irradiated particles of the charged particle beam is equal to or greater than a preset set number of particles, and the irradiation position coordinates of the charged particle beam coincide with the preset set position coordinates A third step of stopping the charged particle beam in any of the cases where the irradiation is not performed; and determining whether or not irradiation of all the irradiation regions has been completed when the charged particle beam is stopped. If not, return to the first step, increase i by one, and change the rotation angle of the scanning field generating means, the field strength, and the energy of the charged particle beam in a predetermined order. A charged particle beam irradiation method including a fourth step of repeating the first step to the third step, and terminating the irradiation if the step is completed, so that an accurate position can be obtained without moving the irradiation object. And a charged particle beam irradiation method capable of accurately irradiating a dose.
[0084]
Further, in the charged particle beam irradiation method according to the present invention, in the fourth step, the rotation angle of the scanning field generating means is kept constant, and the intensity of the field of the scanning field generating means and the energy of the charged particle beam are set to predetermined values. The first step to the third step are repeated while changing in the order described above, so that the number of times of adjustment of the rotation angle having a slow change speed is reduced, thereby shortening the entire irradiation time. We can provide a method.
[0085]
Further, in the present invention, the charged particle beam is bent on a straight line on a plane perpendicular to the incident axis thereof by a scanning field generating means for generating a scanning field consisting of a set of fields which bends the charged particle beam in the opposite directions by the same angle. And the scanning field generating means is rotated about the incident axis to irradiate the irradiation area with the charged particle beam, wherein a coordinate group [(Zi, θij), i = 1, 2,. . , M, j = 1, 2,. . . , N], the first step of setting the energy of the charged particle beam to be irradiated in accordance with the position coordinate Zi (i = 1 as an initial value) of the irradiation depth, and setting the rotation angle of the scanning field generating means to θij ( A second step of setting the time characteristic of the scanning pattern to Iij (t) to j = 1) as an initial value, and irradiating a charged particle beam in accordance with the above setting, and performing the above-described processing using the time characteristic Iij (t) of the scanning pattern. A third step of driving the scanning field generating means to scan the charged particle beam a predetermined number of times, and in parallel with the third step, the irradiation position coordinates of the charged particle beam coincide with preset set position coordinates. A fourth step of determining whether or not the scanning has been performed a predetermined number of times and that the irradiation position coordinates of the charged particle beam match the set position coordinates A fifth step of stopping the charged particle beam when the charged particle beam is not present, and judging whether or not the irradiation to all the irradiation areas has been completed when the charged particle beam has been stopped, and terminating the irradiation if completed. If it is not completed, it is determined whether or not to change the position coordinate Zi of the irradiation depth to the next value. If it is not to be changed, j is increased by one, and the process returns to the second step and returns to the second step. To the fifth step, and when changing, increase i by 1, set j to the initial value of 1, return to the first step and repeat the first to fifth steps. And a charged particle beam irradiation method comprising the steps of: (1) providing a charged particle beam irradiation method capable of irradiating an accurate dose to an accurate position without moving an object to be irradiated;
[0086]
Further, in the present invention, in the above charged particle beam irradiation method, the scanning field generating means performs scanning at one time only over the radius of the irradiation area, and the time characteristic Iij (t) of the scanning pattern is calculated as Iij (t) ∝√. Since t is set, a charged particle beam irradiation method capable of more uniform irradiation can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a charged particle beam irradiation apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the scanning electromagnet of FIG.
FIG. 3 is a perspective side view of the scanning electromagnet of FIG. 1;
FIG. 4 is a diagram showing a particle number density distribution when a charged particle beam irradiation apparatus according to the present invention uniformly irradiates a charged particle beam.
FIG. 5 is a diagram showing the relationship between the scanning distance of an incident charged particle beam and the current of an electromagnet according to the present invention.
FIG. 6 is a diagram showing a time characteristic of a scanning pattern for uniformly irradiating a charged particle beam in the present invention.
FIG. 7 is a diagram showing a time characteristic of a scanning pattern for uniformly irradiating a charged particle beam in the present invention.
FIG. 8 is a diagram showing another configuration example of the scanning electromagnet of the charged particle beam irradiation apparatus according to the present invention.
FIG. 9 is a diagram showing a configuration of a charged particle beam rotary irradiation device according to an embodiment of the present invention.
10 is a diagram showing a structure of a bending electromagnet of the charged particle beam rotary irradiation device of FIG.
FIG. 11 is a diagram showing a configuration of a charged particle beam irradiation apparatus according to another embodiment of the present invention.
FIG. 12 is a diagram showing a configuration of a control system of a charged particle beam rotary irradiation apparatus according to another embodiment of the present invention.
FIG. 13 is a flowchart showing an example of the operation of the control system of the charged particle beam rotary irradiation device according to the present invention.
FIG. 14 is a flowchart showing another example of the operation of the control system of the charged particle beam rotary irradiation device of the present invention.
FIG. 15 is a diagram showing a state in which a charged particle beam according to the present invention is scanned in a radial direction.
FIG. 16 is a diagram showing a configuration of a conventional charged particle beam rotary irradiation device.
[Explanation of symbols]
Reference Signs List 1 particle accelerator, 3 transport electromagnet, 5,21 energy degrader, 9 beam stopper, 10 rotating gantry, 11, 13, 19 deflection magnet, 15 focusing electromagnet, 20 charged particle beam irradiation device, 23 dose / position monitor, 25 Patient, 27 irradiation bed, 29 gantry rotation axis, 30 incidence axis, 31 charged particle beam beam, 33, 35 scanning electromagnet, 37 rotation axis, 45, 47 connection frame, 49, 49a, 49b motor, 53 rotation drive gear, 55 sweep locus, 56 irradiation area, 57 irradiated object, 93a, 93b, 95a, 95b electrode, 97 insulator, 99a, 99b power supply, 100 charged particle beam rotating irradiation device, 102 box, 103 cable, 105 cable connector, 200 Control device.

Claims (8)

By generating a scanning field consisting of a set of fields that bend the charged particle beam by the same angle in opposite directions to each other, the charged particle at the irradiation target is defined as the distance from the incident axis of the charged particle beam to the scanning field. A scanning field generator for changing the irradiation position of the line,
A rotating unit that rotates the scanning field generating unit with the incident axis to the scanning field as a rotation center axis,
Provided between the scanning field generator and the irradiated object, charged particle beam energy adjusting means for changing the irradiation depth of the charged particle beam from the surface of the irradiated object by adjusting the energy of the charged particle beam, ,
The irradiation position information includes preset rotation position information discretely set around the rotation center axis, the rotation radial position information, and the irradiation depth information of the irradiation target. After rotating the rotating unit corresponding to a predetermined rotation angle among the rotation angles included in the position information, based on the radial position corresponding to the rotation angle included in the irradiation position information, and the irradiation depth, By controlling the intensity of the scanning field of the scanning field generating unit , and the charged particle beam energy by the charged particle beam energy adjusting means, and irradiating the charged particle beam, it is included in the irradiation position information corresponding to the rotation angle. After performing the irradiation of the charged particle beam at the radial position and the irradiation depth, irradiation is performed such that the series of the charged particle beam irradiation is performed for another rotation angle included in the irradiation position information. And control means for performing control,
A charged particle beam irradiation device comprising: By generating a scanning field consisting of a set of fields that bend the charged particle beam by the same angle in opposite directions to each other, the charged particle at the irradiation target is defined as the distance from the incident axis of the charged particle beam to the scanning field. A scanning field generator for changing the irradiation position of the line,
A rotating unit that rotates the scanning field generating unit with the incident axis to the scanning field as a rotation center axis,
Provided between the scanning field generator and the irradiated object, charged particle beam energy adjusting means for changing the irradiation depth of the charged particle beam from the surface of the irradiated object by adjusting the energy of the charged particle beam, ,
The rotation angle information discretely set around the rotation center axis, the irradiation depth information of the irradiation target, and the rotation angle, corresponding to the irradiation depth, are substantially inversely proportional to the distance from the rotation center axis. For changing the sweep speed of the charged particle beam, has scanning position information that is a time-dependent function that defines the intensity of the scanning field, and has predetermined irradiation position information, and includes rotation included in the irradiation position information. The angle is controlled by the rotation of the rotating unit, and the irradiation depth is controlled by the charged particle beam energy by the charged particle beam energy adjusting means, thereby controlling the irradiation position, and based on the scanning pattern corresponding to the rotation angle and the irradiation depth. Control means for performing irradiation control so as to perform charged particle beam irradiation in the radial direction of rotation,
A charged particle beam irradiation device comprising: The control unit performs irradiation at a predetermined rotation angle among the rotation angles included in the irradiation position information, the irradiation depth set at the rotation angle, and the scanning pattern, and then performs the irradiation included in the irradiation position information. 3. The charged particle beam irradiation apparatus according to claim 2, wherein the series of charged particle beam irradiation is performed for a rotation angle of. The charged particle beam irradiation apparatus according to any one of claims 1 to 3 , wherein the scanning field generating unit has a scanning field generating unit disposed on one side of the charged particle beam incident axis. Charged particle beam deflecting means for deflecting the charged particle beam so as to be perpendicular to the irradiation surface of the irradiation object,
The charged particle beam irradiation apparatus according to any one of claims 1 to 4 , wherein the charged particle beam irradiation apparatus is installed downstream of the deflection unit with respect to a charged particle beam traveling direction.
Rotation moving means for integrally rotating the deflection means and the charged particle beam irradiation device,
A charged particle beam rotary irradiation device equipped with: Scanning field generating means for generating a scanning field consisting of a set of fields that bend the charged particle beam by the same angle in opposite directions to each other, the incident charged particle beam being perpendicular to the incident axis of the charged particle beam to the scanning field. While scanning on a straight line on the surface, the scanning field generating means is a method of irradiating a charged particle beam to irradiate a charged particle beam to the irradiation area of the irradiation object by rotating the incident axis as a center,
Rotation angle information discretely set around the rotation center axis, radial position information of the rotation, and irradiation depth information of the irradiation object, having preset irradiation position information,
A first step of setting a rotation angle of the scanning field generating means based on the irradiation position information;
The radial position and the irradiation depth corresponding to the rotation angle set in the first step included in the irradiation position information are set, and the scanning field generating means corresponds to the set radial position and the irradiation depth. A second step of setting the field strength and the energy of the charged particle beam;
A third step of controlling the charged particle beam according to the settings in the first step and the second step to irradiate the irradiation target with an object;
With respect to the other radial position and irradiation depth corresponding to the rotation angle set in the first step included in the irradiation position information, the second step to the third step are performed until the unirradiated radial position and irradiation depth disappear. A fourth step to repeat the steps,
A fifth step of repeating the first to fourth steps until there is no unirradiated rotation angle included in the irradiation position information with respect to the other rotation angles included in the irradiation position information;
A charged particle beam irradiation method comprising: Scanning field generating means for generating a scanning field consisting of a set of fields that bend the charged particle beam by the same angle in opposite directions to each other, the incident charged particle beam being perpendicular to the incident axis of the charged particle beam to the scanning field. While scanning on a straight line on the surface, the scanning field generating means is a method of irradiating a charged particle beam to irradiate a charged particle beam to the irradiation area of the irradiation object by rotating the incident axis as a center,
The rotation angle information discretely set around the rotation center axis, the irradiation depth information of the irradiation target, and the rotation angle, corresponding to the irradiation depth, are substantially inversely proportional to the distance from the rotation center axis. For changing the sweep speed of the charged particle beam, having scanning pattern information that is a time-dependent function that defines the intensity of the scanning field, having irradiation position information set in advance,
The charged particle beam energy based on the irradiation depth included in the irradiation position information, the rotation angle of the scanning field generating means based on the rotation angle corresponding to the irradiation depth, and the scanning pattern corresponding to the rotation angle and the irradiation depth are set. A first step to
A second step of scanning the charged particle beam based on the set irradiation depth, rotation angle and scanning pattern and irradiating the irradiated object with the beam;
A third step of repeating the first step and the second step until there is no unirradiated rotation angle included in the irradiation position information;
A charged particle beam irradiation method comprising: At a predetermined rotation angle among the rotation angles included in the irradiation position information, the irradiation depth set at the rotation angle, and after performing irradiation with the scanning pattern, the other rotation angles included in the irradiation position information are used. The charged particle beam irradiation method according to claim 7, wherein the series of charged particle beam irradiations is performed.

Images